Panasonic TC-P55GT50 12 Blinking lights?

[Freeflynick]

Hello!
DISCLAIMER! I am a mechanical engineer, so unscrewing the back panel and pulling a few connectors is about the limit of my capabilities!

Last week our Panasonic Viera TC-P55GT50 (about 6 years old I think) started switching itself off and giving 12 (twelve) blinking lights. It started doing this more frequently until now it usually will not even show a picture before giving the 12 blinks.
I took the back off and after reading some threads on similar models I unplugged the power and ribbon to the (I think - it is the board on the left in the attached photo) YSUS board, turned on the power and got 7 blinking lights. After re-plugging power and ribbon to the YSUS, the TV stayed on for a few minutes before again showing 12 blinks.

Any advice on either further troubleshooting (but you will have to dumb it down a little!) or potential fixes would be greatly appreciated!

Cheers!

Nick

[tw2005]

Re: Panasonic TC-P55GT50 12 Blinking lights?

only have time to give this info.
12 blinks labelled as an audio fault.

could be mainboard issue or speakers

Defective Speaker/Subwoofer
Pinched Speaker Wire
Wrong diagnostic by the A board

[dj01fad]

Re: Panasonic TC-P55GT50 12 Blinking lights?

Hi Nick,

12 blinks is the sound SOS. check the speakers first, and if they are all OK, then... the problem can come from A board. disconnect the speakers / woofer and see if the TV will work this way. Also, check the speakers impedance.

later edit: same time post

[Freeflynick]

Re: Panasonic TC-P55GT50 12 Blinking lights?

Thanks for the responses!

If I unplug the speaker and everything works OK is there any problem with leaving it unplugged and running all sounds through my receiver?

Any tips on how to check the speaker impedance and what value I would be looking for?

Thanks again!

[dick_barton]

Re: Panasonic TC-P55GT50 12 Blinking lights?

Use your ohm meter to check speaker resistance with the speaker disconnected.

[Freeflynick]

Re: Panasonic TC-P55GT50 12 Blinking lights?

On the 200k setting I read 22ohms across the speaker (connecting to the two pins in the wee plug to the speaker).

I also tried disconnecting the speaker and continued to get the 12 blinks.

Any further advice?

[tw2005]

Re: Panasonic TC-P55GT50 12 Blinking lights?

May have no choice but to get the A-board repaired.

http://www.ptselectronicsinc.com/txn-a1rauus/

[Freeflynick]

Re: Panasonic TC-P55GT50 12 Blinking lights?

This morning I tested the speaker again, this time on the 200ohm setting and it read around 160. I'm not going to pretend that understands how those scales work! Which millimeter setting should I be testing the speaker with and what readings should I get?

Anyway, TV is still coming on for about 2 minutes before clicking off and giving 12 blinks, with or without speaker plugged in. Does anyone second tw2005's recommendation of replacing the A board? (No offense tw2005.....just want a second opinion before I pull out my wallet!).

Can anyone give me a brief description of what the A board does and what is likely to have gone wrong with mine?

Thanks again guys.....looks like I definitely found the right resource here - great website.

[vinceroger69]

Re: Panasonic TC-P55GT50 12 Blinking lights?

i would trust tw2005 diagnosis he knows his panasonics very well so i would certainly go with the a board replacement just make sure you get if from seller where you can return the board it if its faulty as not all sellers test all boards to fully make sure they work or get the board repaired by a company who offers a gaurantee on there work etc

[tw2005]

Re: Panasonic TC-P55GT50 12 Blinking lights?

This morning I tested the speaker again, this time on the 200ohm setting and it read around 160. I'm not going to pretend that understands how those scales work! Which millimeter setting should I be testing the speaker with and what readings should I get?

Anyway, TV is still coming on for about 2 minutes before clicking off and giving 12 blinks, with or without speaker plugged in. Does anyone second tw2005's recommendation of replacing the A board? (No offense tw2005.....just want a second opinion before I pull out my wallet!).

Can anyone give me a brief description of what the A board does and what is likely to have gone wrong with mine?

Thanks again guys.....looks like I definitely found the right resource here - great website.

pretty sure the speakers will be 6 ohm, maybe 8 ohm tops.

I tried looking at a schematic but not enlargeable with any clarity but there appears to be 2 amp ICs. One for the woofer, one for L/R spkrs.

If you got Hot Air you may be able to replace the chips assuming they're at fault but it may be the monitoring IC that's defective too I guess causing a false trigger.

You'd have to get a look at a schematic and work out if either IC4900 or 4901 are putting out a SOS level.

From what I can just read, pin 22 on these ICs is the error line and a high is operate, if it's low = error and shutdown.

I don't know what more to suggest, forcing a high may allow it to operate but at what risk?

Since it appears you can't get a board used and over $300 + core exchange at Encompass the PTS option may be it.

may be set your meter to a closer range, I doubt the speakers are reading 160 - 200 ohms.

I have not had to deal with a 12 blink audio fault so I can't talk from experience with this one.

[vinceroger69]

Re: Panasonic TC-P55GT50 12 Blinking lights?

As these boards are not easyily available this must be quite a common problem with the a boards.

[dick_barton]

Re: Panasonic TC-P55GT50 12 Blinking lights?

Use the ohms range on your meter across the speaker terminals. Unplugged the terminals if you have to connected to the speaker. It's ohms not millivolts you need to read. And I would expect <<16 ohms and as TW2005 said they are probably 8 ohm speakers which is standard.

What is the audio ampflier part number?

[dj01fad]

Re: Panasonic TC-P55GT50 12 Blinking lights?

If on 2 readings the values are 20 and 160 ohms, something is not right. check again, maybe you had bad readings. the normal value I guess it's 6-8 ohms. also: connect the 2 pins together on the 200ohm scale, and if you don't read 0 or 1-2 ohms, then you have a problem with the ohm-metter. all the speakers have the same value? including woofer?
when the TV is on, the sound is normal? all the speakers are working ok?
you disconnected the speakers from the a board, or from the speakers? try do disconnect the a board speakers connector if you did the other way. like tw2005 said, it is possible to have a pinched wire...

[Diah]

Re: Panasonic TC-P55GT50 12 Blinking lights?

you need to reset ( Clear ) the error code at service menu, other wise will not working as usual,

[Freeflynick]

Re: Panasonic TC-P55GT50 12 Blinking lights?

More great info guys - y'all rock!

Diah - how do I clear the error codes? Not sure how to get into the service menu.....

[tw2005]

Re: Panasonic TC-P55GT50 12 Blinking lights?

you need to reset ( Clear ) the error code at service menu, other wise will not working as usual,

Is this a new feature? Can't say I've seen this before up to 2011 at least

[tw2005]

Re: Panasonic TC-P55GT50 12 Blinking lights?

More great info guys - y'all rock!

Diah - how do I clear the error codes? Not sure how to get into the service menu.....

Try holding vol - on the tv whilst on the remote repeatedly push info button. Can be different in other regions.

Or start searching here your model or say 50" model for service manual or elektrotanya

[Malachi]

Re: Panasonic TC-P55GT50 12 Blinking lights?

I put the A board from my bad Tc-p55vt30 in my Tc-p55gt30 and it works fine. Tv thinks it's a 55vt30. Lol
Maybe you can try a board from a different model of the same line? Idk, I don't know much.

[Diah]

Re: Panasonic TC-P55GT50 12 Blinking lights?

Is this a new feature? Can't say I've seen this before up to 2011 at least

no its not new, if you own the service manual please read the section of clear error code, and this at most TV too. its not only history error code, but firmware read this section at NVM before it go next step.

Not sure how to get into the service menu.....

tw2005 wrote it already,, for me i use apk on android always to get in any step of service menu at any TV

[tw2005]

Re: Panasonic TC-P55GT50 12 Blinking lights?

no its not new, if you own the service manual please read the section of clear error code, and this at most TV too. its not only history error code, but firmware read this section at NVM before it go next step.


tw2005 wrote it already,, for me i use apk on android always to get in any step of service menu at any TV

Can you take a snapshot of this in the manuals and post it please. I can't find it and I don't understand NVM. (unless non volatile memory? )

All I read briefly was a self check will clear the SOS history of the last 3 events but not the first or second event from shipping.

"This indication except 2nd and 1st occurrence after shipment will be cleared by [Self-check indication and forced to factory
shipment setting"